


A Study in Salt and Blood

by blessedjessed



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Demon!Sherlock AU, First Kiss, First Time, Inspired By Good Omens, M/M
Language: English
Status: In-Progress
Published: 2012-12-09
Updated: 2012-12-09
Packaged: 2017-11-20 17:44:10
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,893
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/588038
Author URL: https://archiveofourown.org/users/blessedjessed/pseuds/blessedjessed
Summary: <blockquote class="userstuff">
              <p>Someone has been killing London's demons, and Sherlock Holmes (fallen angel and connoisseur of the darker sides of the human psyche) wants to know why.  But the killings are more complicated than they seem, his flatmate is hiding something from him and Sherlock is beginning to wonder if he's next on the list.</p>
            </blockquote>





	A Study in Salt and Blood

**Author's Note:**

> For [reapersun](http://reapersun.tumblr.com/), as part of the [November Johnlock Challenges gift exchange.](http://johnlockchallenges.tumblr.com/)

The shape materialised inside the circle slowly, and then all at once – a vague dark swirl that grew by increments and then sharpened suddenly into a long, spare figure in a black suit.  His hair was raven-black, and his skin pale and flawless.  Oddly enough, he was fiddling with a mobile phone.  There was a long silence, each of the three people behind the dark robes glancing at one another, willing someone else to speak.  The candlelight flickered over the bare room.  At long last someone cleared their throat.  
  
“Demon, I abjure thee…” began a voice, wavering, young, male. It emanated from the hooded figure who might well be the leader, as he clutched a large tome in his trembling hands.  
  
“Dull,” sighed the demon, his pale eyes never leaving the phone.  There was another silence, this one with an edge of resentment over the terror and uncertainty.  
                                     
“I _command_ thee to listen to my demands!” snapped the leader, irritation distinct in his voice.  
  
“Hearken,” said the demon, pressing another button and making his phone emit a whooshing noise.  
  
“What?”  
  
“The correct term in that sentence should have been “hearken.” If you’re going to use archaic language, at least be consistent.”  The demon slipped the phone back into his pocket and his head snapped up, fixing the leader with a stare from silvery eyes, making him gasp and almost drop the book.  “The robes, the candles, the protective circle formed of goat’s blood and salt – you’re aiming for traditionalism but you’ve missed by a mile.  The very least you could have done is find a decent summoning ritual.”  
  
“We summoned you here - ”  
  
“ _Hence._ ”  
  
“I…um…we summoned you hence to negotiate a deal with your great master,” continued the book-holder, after flapping his jaw a few times.  
  
“Wrong.”  
  
“But…”  
  
“You.”  The demon pointed straight to his left, following his outstretched finger a second later with his intense stare, making the hood’s owner shy backwards.  “Small, skinny, awkward posture as though you were trying to hide behind your own bony ribcage.  Acne scars, too, from what I can see of your chin.  You would trade your soul for the chance to revenge yourself on those who tormented you in school.  Hardly cost-effective.  Take an axe to each of their skulls and you’d have your revenge and have consigned your soul to hell without the need to ruin a perfectly good parquet floor with bloodstains.”  
  
“You are more complicated,” the demon continued, snapping his head to his right.  “But not nearly complex enough to be interesting.  Hand-me-down jeans and an old, torn sweatshirt?  You have an older sibling, but neither are you as cosseted or as spoiled as the youngest would be.  A middle child, then, and complete with all the inferiority complexes so stereotypical of your type.  You’re not as possessed with homicidal rage a spotty over there, but your need for attention is almost pathological.  Going by the collection of disgustingly grimy concert wristbands on your arms I’d judge you want to be a rock star.  Hardly original.”  
  
“And _you_ …” he looked at the leader this time, a contemptuous smirk blossoming onto his face.  “Are you really so desperate for affection that you’d pay your soul to a demon to make little miss middle child over there love you?”  There was a gasp from the woman in question but the demon kept his unnerving eyes locked on the leader.  “But then again, your pathetic and clichéd desires are not why I’m here.  I’m here because you intended to lure me into a trap, and then kill me.”  This time the leader really did drop the book, and the demon sneered.  “ _That_ is the only interesting fact about you.”  
  
“It-it worked, though!”  The leader pulled himself together, straightening his shoulders.  As an afterthought, he flung back his hood, eyes wide in his young face and sweat beading on his forehead.  “You’re here and you’re trapped, and I’ve found a ritual…that will… _ohgodno_ …”  
  
There was something dreadful where the demon had been.  
  
A moment later, when the three would-be demon slayers had succumbed to unconsciousness, the demon resumed his former shape.  
  
“Amateurs,” he sighed, brushing a stray maggot from his lapel.  He made a complicated gesture with his left hand, and the ring of salt blew away.  He walked forward, pausing by the fallen girl and looking down at her.  Yes, there it was, peeking above her collar – a little glimpse of pink, as he’d noticed on the others.  He stooped, retrieved it, and squinted in the candlelight.   _Curious_ , he thought.  Then, he tucked it into his pocket, walked to the door and stepped out into the night.  
  
*  
  
“Anything interesting?” asked John from the sofa as Sherlock slammed the door behind him. The TV was on and he was halfway through his second cup of tea - evidently he’d been planning on a quiet night in.  221B Baker Street was warm, cozy, cluttered - exactly as he’d left it when he swept out.    
  
“What do you make of this?” Sherlock thrust out the amulet he’d taken from the hooded girl.  John blinked, tilting his head slightly back, attempting to focus on the slightly swinging thing.  
  
“It’s pink,” he said after a moment, and Sherlock bit back the “why do I keep you around?” on the tip of his tongue.  If he insulted John now he ran the risk of having a row, and he wanted John’s help.  This was a complicated and knotty problem and the skull wouldn’t suffice tonight.  Besides which, he had no adequate answer to that question.  Precisely why an immortal demonic force needed a flatmate, he didn’t know.  But he had a John and he’d like to keep it that way.  For tonight, anyway.  At least until he’d solved these murders.  
  
“A perfectly sound analysis, but I was hoping you’d go deeper,” replied Sherlock dryly, settling for sarcasm.  
  
“Yes, all right,” he grumbled, twitching the amulet out of Sherlock’s hand.  He rolled it between his fingers, a small, pale pink medallion carved with three strange symbols.  John pursed his lips.  “Well, I can’t feel anything coming from it.”  
  
“Yes, it’s completely unmagical.”  Sherlock began to pace across the rug, his fingers steepled below his chin.  
  
“You’re doing that look again,” said John, raising an eyebrow.  “You already know what this means.”  
  
“Don’t you?”  Sherlock turned sharply, and gave him a glare that said _“keep up, John.”_ John returned one that said _“make a comment about my intelligence and I will punch you in the face.”_  Sherlock looked away first.  
  
“…no.”  
  
“Three arcane symbols on a strange amulet, worn by each member of a cult,” Sherlock paced again, one hand behind his back and the other gesticulating in time with his deductions.  “Even if those symbols were completely made up, the mere focus of belief should have been enough to imbue them with _some_ sort occult influence.  Instead there isn’t a single trace of anything on it.  And the symbols themselves, John, what do you make of them?”  
  
“I…don’t recognise them.  Nothing I’ve ever run into before.”  John frowned down at the amulet, as though looking for something he’d missed.  
  
“ _Exactly_.  The three I ran into tonight were sticklers for tradition.  If they’d had their way, they would have had every known charm symbol in history carved on the amulet, but instead, we get three completely unknown ones.  They weren’t creative enough to come up with the symbols themselves – they were still using salt and goat’s blood.”  
  
“Haven’t seen that in a while,” mused John.  
  
“Indeed.  So what made them think they were powerful enough to kill a demon?”  Sherlock finally paused and stared at John.  This was the tipping point; there were too many question now, and some of them must start spilling over into answers.  It was just beyond his reach, and all he needed was one spark, one beam of light from John and he’d be there, he knew it...  
  
“Well, how do you… _Sherlock_.  You answered that summons knowing full well they would try something, didn’t you?”  
  
Sherlock blinked, his expression the one of someone who’s train of thought has just derailed at a sharp turn in the line.  John’s mouth had turned tight and angry, and his forehead puckered with a frown.   _Ah_.   _Demons are dying, and I sauntered off to meet the people I thought were responsible.  John disapproves.  Sentiment._ Sherlock rolled his eyes and slumped into his favourite chair.  
  
“John, do _try_ to have a little faith in me.  I would hardly have gone if I thought that I would meet anyone who could actually hurt me.”  
  
“A demon asking for faith?  That’s rich! Sherlock, what if they had discovered something that could kill you?  They’ve killed three demons so far – you could have walked straight into a trap!” John was sitting forward now, his face earnest and exasperated.  
  
“I _did_.  And as you can see, John, I walked straight back out again.  And it’s four, now.”  
  
“Four?  Who else is gone?” John had gone still, the agitation dropping from his posture. His mouth set in worried lines.  
  
“Furcas.  He tried to contact me just before his end, but I was distracted by my encounter with the amateur demon hunters.” He had been texting him, in fact. The last message had been a blank one. Sherlock had assumed the worst and had it confirmed through his contacts.  
  
There was a long pause in the room.  Furcas had been powerful – an old boy, set in his ways and if you were going to lure anyone to their deaths, he would probably have been the easiest one to capture. Even texting had confused him - the modern world was something to be feared and shunned. Still, faded though he was, Furcas had been on Earth since the Beginning. He was ancient, powerful, and extremely hard to kill. But someone had. Someone had killed three others of his kind, too, and Sherlock didn't know how. But when he looked at the amulet in his hand, something small and urgent in the back of his mind told him he knew why.  
  
“Sherlock, this is bad." John was running his hands through his hair, making it stick up. The anxiety lines were back around his eyes and Sherlock knew what he would say next. "What if they were just the distraction?  Summoning you like this might mean that they’ve noticed you’re investigating, and…”  
  
“That I’m next?  Yes, _thank you_ , John, but I had thought of that," he snapped. Anything to stop John looking at him like that. "And why the concern, anyhow? Surely it would solve an awful lot of your problems if your demon housemate suddenly winked out of existence.  Fewer biohazardous items in the fridge, for a start.”  
  
Sherlock knew the second the sentence left his mouth that it was Not Good.  It was more than slightly not good, in fact, and he didn’t need to see the sudden blankness on John’s face to know it.  John looked at him for a long moment, and drew a breath in as if he was going to speak.  Then he let it all out in a single huff and started pointedly at the telly.  Sherlock huddled in his chair, waiting for something to happen – what, he wasn’t entirely sure.  Half of his brain was chasing the meaning of the amulet and the robed cultists in circles, knowing he didn’t have enough data to deduce it yet. The other was wondering when John would start talking to him again.  Almost half an hour passed in stilted silence before Sherlock decided he was bored with the whole world and broke it.  
  
“Get your coat on, we’re going to dinner.”  
  
“What? No, it’s almost nine and I’m comfortable now.”  
  
Sherlock wordlessly threw John’s jacket at him and knotted his own scarf around his neck.  John stood (or, more accurately, sat) his ground for thirty seconds longer, before standing up and following Sherlock out of their flat.  
  
*  
Dinner, unless explicitly specified, always meant Angelo's. It served the only food Sherlock would eat (when he wasn’t eating to look human or complete a scheme) and besides, he enjoyed the irony the name. The restaurant was in Soho, and therefore meant a decent walk from their Baker Street address, but John hated to get the tube and tonight Sherlock wanted to see the city. London was an excellent place to be a demon in. Most of his kind had deserted the old cities of Europe, moving to North America where they could shake the balance of the world, or else spreading out across Asia and Africa, finding new and exciting vices to promote. There were a fair few still around (some had recently got a commendation for the European banking crisis) and Sherlock intended to stay one of them.  
  
He'd come to London during the plague of 1665, had a minor supporting role in the Great Fire of 1666, and had liked the city so much that he'd stayed. He'd almost resented Britain's rise to Empire in the eighteen-hundreds as it meant it was a sudden focus of other demons. He'd wanted to tell them to piss off and leave his lovely sinful home alone.  All those occult forces, pulling this way and that, cluttering up the metaphysical atmosphere for miles around - it had set Sherlock’s teeth on edge and lead him to spend most of the nineteenth century in a quiet back-alley of Soho.  Not that Below had noticed that he was in dereliction of his duty - he'd been praised to Low Hell for the Jack the Ripper murders, even though he'd had nothing to do with them. He had just tracked the man down, out of sheer fascination, and observed the descent of a human mind into complete madness. (Although he'd caught up in the middle of the Mary Kelly murder. He'd watched for ten minutes and then found the nearest opium den and lost his mind for a week).    
  
And then the Empire had fallen, everyone had moved away and London was Sherlock’s playground again.  He didn’t bother with the tempting these days.  For a start, it was dull - yes, it was something of an art form, the old-fashioned way of chipping away gradually at one soul, slowly gathering them into hell.  But it got repetitive and besides which, there were too many of them, these days.  And if you let them, humans would do most of the work for you.  That was what made Sherlock's life as one of the denizens of Hell so bearable.  Humans had imagination. Oh, they were an extremely dull bunch, for the most part - all scurrying about, looking for food and sex and money. But when they decided to become evil, oh, the sheer malicious glory of it! They were fantastic at it - they would sit down and think up some far-fetched nastiness that all the demons in Dis couldn't concocted in all of recorded time, and then blame it on the Devil. Or, occasionally and more amusingly, God.  Hell wasn't a fount of pure evil just as Heaven wasn't (in Sherlock's opinion) a source of pure good. Where you found the real, stomach-churning evil, and the pure, heart-melting grace was humans. And Sherlock, in the twin grips of revulsion and admiration, had made it his life's study. He ignored the missives from Hell, these days. _Give up_ , he wanted to tell them. _Pack up Tartarus and Pandaemonium. Disassemble all those instruments of torture and fear, and move up here. They've got it sorted better than we ever could._  
  
They sat in their usual seat, by the window (it was always free – as far as Sherlock was concerned, table reservations were things that happened to other people.) John’s expression was tight, his gaze deliberately anywhere but Sherlock.  He was still angry, and he managed to stay that way all through the starters, until the waiter cleared their plates away and Sherlock was absently rolling the charm in his fingers and frowning in thought.  
  
“So,” John cleared his throat, his fingers fidgeting with the stem of his wine glass as Sherlock returned from his train of thought and zeroed in on him.  “Who’s been killing all of London’s demons?”  
  
“Oh?”  Sherlock smirked.  “So _now_ you’re interested.”  John rolled his eyes.  
  
“Doesn’t mean I’m not still angry with you,” he grumbled.  “You could have been killed.”  
  
“Surely from a purely ethical standpoint, that would have been a good thing,” he smirked.  “By definition, demons are bad, and therefore killing one is a good thing.”  
  
“Then who would pay your half of the rent?” asked John, around a mouthful of seafood linguine. He shook his head, and swallowed.  “But demons are sentient.  Killing one is murder.  You can’t decide that just because someone deserves to die, you get to kill them.”  
  
“Are you implying that I deserve to die?” Sherlock raised an eyebrow.  
  
“Well, you _did_ invent the customised ringtone.  And you still haven’t answered my question.”  
  
“I don’t know.”    
  
John looked up, eyebrows raised.  
  
“Yes, all right.  The scenes I have examined don’t conform to any sort of stereotype.  Normally with this sort of thing there’s an element of worship, whether of Hell or Heaven. But there was nothing.  Just the paraphernalia necessary for the ritual and the pink charms.  So we’re dealing with a cult powerful enough to destroy a Knight of Hell - not just banish him, actually dissolve him from existence - and yet they seem to be completely unmagical, almost entirely atheist and...”  
Sherlock stared past John, out of the window.  “And apparently ready for round two. _Don’t_ look.  A young man has just walked past the window for the second time.  Normally not anything to worry about but he passed the window going the same way both times and...” Sherlock grinned.  “There was something pink around his neck.”  
  
“Looks like we’ll be having an interesting walk home.”  
  
“Doesn’t it just?”  
  
*  
Once outside they walked fast.  They had taken a little longer than Sherlock would have liked leaving the restaurant (bills were something that happened to other people, too, but John had insisted on not defrauding an innocent restaurant owner) and had lost sight of the lurking cultists.  It was less than optimal, but if they were anything like the cultists he’d run into earlier, they’d be easy enough to take care of, with John at his side. He weighed the options he had; he’d prefer not to utilise every demonic option available - a discharge of occult power that large would alert numerous unsavoury things, and quite possibly bring something looking.  He could use the hell-form again (it had worked last time) but then he hated to do that.  Useful though it was, it was always attended by a niggling fear that he’d forget how to turn back.  Of course, he could always ask John to deal with them...  
  
“Oof!”  
  
That was as far as Sherlock could get with his plans because, as he rounded the corner of Poland Street, someone walked into him.  He was ready to snap at the man as he stumbled back, when he caught sight of his face and thought _I recognise that scarred chin_.  The cultist (Sherlock mentally named him Spotty) whimpered, and then turned and ran, sprinting towards D’Arblay street.  Sherlock launched into a run, hearing John sigh “Oh, for the love of...” before following.  They chased him, dodging the various night-people of Soho, across Berwick Street dodging taxis (he heard John apologising behind him).    
  
“Come on, John,” he yelled, and sped on, almost within grabbing distance as they ran across Wardour Street.  Sherlock felt a grin on his face.  This was fun.  
  
A very familiar voice yelled in pain, some way behind him.  Sherlock whirled, and distracted by the sudden and dismaying lack of John, didn’t move in time to avoid a glancing blow to the back of his head with what felt suspiciously like a traffic cone, and went sprawling.  He landed hard on his hands and knees, and momentarily his thoughts wandered. _Six thousand years_ , he thought, time seeming to slow as the cultist ran up behind him.   _Six thousand years I’ve been on this ridiculous planet.  If they’ve hurt him..._  
  
The seams of Sherlock’s jacket split, and feathers arced towards the sky.  It would have surprised some to see that the feathers were white, but then, Sherlock had been an angel once.  It certainly surprised Spotty, as the average wingspan of an angel or a demon was more than 16ft, and he met all that length of feather and flight muscle coming the other way and accelerating fast.  He flipped over, hit his head against a shop window, and then was still.  Sherlock set off at a run (the road was too narrow to take flight - he may have been metaphysical but he certainly wasn’t incorporeal.)  He felt his true form becoming evident - teeth lengthening, talons escaping, and he had no doubt his eyes glowed with unholy silver light.  He skidded around the corner, ducking into a dark little alleyway to find John pinned against the wall, two men holding his arms and Little Miss Middle-Child pressing a nasty-looking knife to his throat.  Sherlock glared, and felt a savage sense of victory as they shied back at this shimmering, fanged apparition.  
  
“Get. Away. From. Him,” he snarled.  
  
“Get back, demon.  Or we’ll send your friend to hell before you,” she glared at him, seemingly unfazed by the winged, snarling man.  Sherlock’s eyes darted around the alley, analysing what was to be done.  He was outnumbered three to one, which would not normally have been much of a disadvantage, but _John_...  
  
“We are doing God’s work,” she proclaimed, and Sherlock realised that while the cult as a whole might have been atheist, she was a zealot and he had badly miscalculated.  His heart beat faster a moment before he heard John growl.  
  
“Oh, you _really_ aren’t.”  
  
Sherlock had just enough time to screw his eyes shut before the heat and bright light filled the alley.  He threw up a protective arm, and ducked behind the shelter of a wing.  Even then, he felt like his feathers were singeing.  He heard three screams as Middle-Child and her cronies were blinded and burned.  He heard them start to run away, stumbling against the walls and felt the bright light dim and the heat begin to cool, and risked a peek through his eyelids.  John’s halo was fading, the pure white glow from his skin fading to a mellow, pearlescent sheen.  
  
“Sherlock,” he said, and there was something else in his voice, something that suggested a greater power than just the unassuming man in a bad jumper who stood before him.  His eyes were still shining gold, although they faded to their customary blue as he stepped forward.  “Are you all right?”  
  
“Yes, fine,” but Sherlock stared at him.  It had been a long time since he’d seen John’s full angelic form, but he wondered how he could have missed it.  “You didn’t use your wings.”  John blinked at him a moment.  
  
“I think the full-brightness halo was enough, don’t you?  And on that subject, winch yours in before someone spots us.”  
  
Sherlock obeyed, but only because he was flicking through the long history of their Arrangement and realising that not once had he ever seen the angel use his wings.

**Author's Note:**

> Huge thanks to my fantastic beta Britt, and my tireless cheerleader Ambra, for putting up with my insecure whining and getting this fic sorted.


End file.
